Guide To Disable EGR & AIV Without Removing.

porkpie700

Buy & Sell Member
Intro;
This is an extremely easy and 100% reversible guide on how to disable the Exhaust Gas Recirculation system on K10 Micra's fitted with the ECC 1.2 engine.
The method shown in this guide will cause no harm or damage to your car (Unless like me, you have a bit of a belly and tend to dent the wing while leaning on it).

Why Do It?
People seem to think that disabling the EGR will somehow turn their car into a rocket... sadly this is a myth. What it does do however is allow the engine to breath more easily, taking in only nice clean air instead of choking on it's own waste gases.

The EGR system has a major flaw, in that it causes unstable idling & hesitation when it's in operation. For example; Stick one end of a pipe to your nose... then insert the other end into your "waste gas outlet" and see how far you can run before feeling ill.
(Kids; please don't try that at home, or anywhere for that matter!) :sick:

How to Do It

The first step is to disconnect the vacuum pipe from the EGR Valve/Diaphram.
Next plug up the end of the vacuum pipe with an air-tight terminator, or "cap".
Secure it.
Slide a small section of spare pipe onto the exposed nipple to keep it covered and protected.
That's it!

"But i need to remove the metal pipe and weld up the hole you stupid man!"
Erm, no you don't, because with the EGR Valve now disabled, that pipe is completely sealed off. So why make extra work for yourself?

Here are some pictures to help explain things;

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Don't forget to secure the now disconnected vacuum pipe to something (as shown in the picture).
Sliding the little bit of pipe onto the nipple is optional but advisable if you want to prevent it from getting dirty or corroding. Note that it is important to leave the nipple open-ended (not blocked off).
The reason being is that if you were to seal-off the EGR nipple itself there would be a possibility that when the engine becomes cold, the air trapped inside the diaphram will contract and create a partial vacuum, thus opening the valve partly.
So don't seal it off!

Next up is a picture of my home-made terminator "cap", which is basically an elbow joint with one of the openings crimped with hot pliers and the end melted, sealing off the second opening.
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AIV System
The Air Induction Valve is designed to allow fresh, filtered air to be drawn into the exhaust manifold when the engine is at a certain temperature and the manifold pressure is low.
The thinking being that the oxygen being drawn in will allow any unburned fuel (Hydrocarbons or "HC") to ignite and burn off before the reach the Catalytic Converters.

This of course makes sense; it's a noble effort to protect the cats from overheating due to fuel saturation. However if the mixture is correct, if the Throttle Open Control system is working, if the Lambda sensor is working, if the ECU is working, if the dashpot is working… the mixture will be correct and there will be no unburned fuel.
(By the way for you non-cat K10 owners, the "rally pop" you get from your exhaust is caused by unburned fuel igniting in the hot manifold. Thus is why a healthy ECC K10 should never or at least rarely pop).

The downside of course is that the addition oxygen present in the exhaust manifold is then picked-up by Mr Lambda sensor, who then tells Mr ECU that there is too much oxygen in the manifold because the mixture is too lean. Mr ECU has no idea that the extra oxygen is not his fault and responds by reducing the amount of air and increasing the amount of fuel that flows through the Electronically Controlled Carburettor.

When the AIV stops pumping air into the manifold, Mr Lambda has a heart-attack and thinks that the mixture is way too rich and then the reverse happens, the correct mixture is eventually regained and order is restored... untill the AIV opens again that is.

But what side-effects does this cause? "Hunting" is what i call it.
You'll be driving along at say 50mph in 5th gear and suddenly notice a slight jerk as the engine seemed for a moment to try to pull-away and then die-off again. Like a pogo stick effect but less regular and much less violent.

In short disabling the AIV will allow the Lambda and the ECU to get a true reading of what the mixture is, and will help the ECU immeasurably to maintain a mathematically perfect fuel-to-air ratio (mixture). The car will drive naturally and consistently, no more "Jackal & Hyde" behaviour from the engine.
(Y)

How To Do It

Same principal as the EGR Valve, it's just a different pipe in a different place.
On the right side of the airbox there is a square build-out with a big fat pipe connecting it to the exhaust manifold. Look under that box...

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Now you know where it is let's take a closer look at the little critter.

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Disconnect the vacuum pipe, seal it, then secure it to something. Just as we did with the EGR pipe, and remember slide a little bit of open-ended pipe (remember not to seal the nipple) onto the nipple to protect it (i removed it on my engine to get a clear photo of the valve, i didn't forget it lol).
A handy place to tuck the vacuum pipe is up behind the boost sensor pipe.

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Reversal is simply reconnecting the vacuum pipes.
That's all folks, if you have any questions about the subjects covered in this guide just drop me a PM.
Professor Porkpie *geek*
 
:D your "Why do it?" part made my day :D
I like, that you say that it is a myth!!! Thank you, many people don't believe it, but it does not give you more hp!
But I still recommend a custom exhaust manifold instead of disabling the egr, because the manifold is the worst thing on this engine. While the inlet manifold is one of the best designed I have ever seen, the exhaust manifold is just terrible! If you replace this it should really give you a power gain.
I am very happy, that I don't have the whole EGR and AIV crap on my micra :D
 
I would also like if someone could reupload the pictures. Also, as you say, Air Induction Valve, is that the same thing as Air Injection Valve? I can't find anything about Air Induction Valve in the repair manual. I think I did it right anyways, but it would be nice with some pictures to confirm! I was going to take pictures as I did it but I forgot. I maybe can do it tomorrow and upload them here, but someone else will have to confirm that I've done it right ;)

Thanks for the guide.
 
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